Heat treatments may introduce some deficiency into Cu\(_2\) O.
An enhancement in \(^{63}\) (1/\(T_1\) ) is reported in a low-temperature prepared Cu\(_2\) O [1]}.
The electric conductivity as a function of temperature \(T\)  = 300\(-\) 500 K indicates an activation energy of 0.26 eV [2]}.
This is smaller than the band gap energy but larger than the present \(\it \Delta \) . Cu\(_2\) O with low carrier concentration is theoretically a potential thermoelectric material [3]}.
The present isotopic analysis may also be a helpful tool to investigate further carrier doping effect on Cu\(_2\) O.
